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<title>Using Annotations to Configure Managed Beans - The Java EE 6 Tutorial</title>
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      <td width="400px"><p class="toc level1"><a href="docinfo.html">Document Information</a></p>
<p class="toc level1 tocsp"><a href="gexaf.html">Preface</a></p>
<p class="toc level1 tocsp"><a href="gfirp.html">Part&nbsp;I&nbsp;Introduction</a></p>
<p class="toc level2"><a href="bnaaw.html">1.&nbsp;&nbsp;Overview</a></p>
<p class="toc level2"><a href="gfiud.html">2.&nbsp;&nbsp;Using the Tutorial Examples</a></p>
<p class="toc level1 tocsp"><a href="bnadp.html">Part&nbsp;II&nbsp;The Web Tier</a></p>
<p class="toc level2"><a href="bnadr.html">3.&nbsp;&nbsp;Getting Started with Web Applications</a></p>
<p class="toc level2"><a href="bnaph.html">4.&nbsp;&nbsp;JavaServer Faces Technology</a></p>
<p class="toc level2"><a href="giepx.html">5.&nbsp;&nbsp;Introduction to Facelets</a></p>
<p class="toc level2"><a href="gjddd.html">6.&nbsp;&nbsp;Expression Language</a></p>
<p class="toc level2"><a href="bnaqz.html">7.&nbsp;&nbsp;Using JavaServer Faces Technology in Web Pages</a></p>
<p class="toc level2"><a href="gjcut.html">8.&nbsp;&nbsp;Using Converters, Listeners, and Validators</a></p>
<p class="toc level2"><a href="bnatx.html">9.&nbsp;&nbsp;Developing with JavaServer Faces Technology</a></p>
<p class="toc level2"><a href="gkmaa.html">10.&nbsp;&nbsp;JavaServer Faces Technology Advanced Concepts</a></p>
<p class="toc level2"><a href="bnawo.html">11.&nbsp;&nbsp;Configuring JavaServer Faces Applications</a></p>
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<p class="toc level3"><a href="">Using Annotations to Configure Managed Beans</a></p>
<p class="toc level4"><a href="#gircr">Using Managed Bean Scopes</a></p>
<p class="toc level5"><a href="#girep">Eager Application-scoped Beans</a></p>
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<p class="toc level3 tocsp"><a href="bnawp.html">Application Configuration Resource File</a></p>
<p class="toc level4"><a href="bnawp.html#giqck">Ordering of Application Configuration Resource Files</a></p>
<p class="toc level3 tocsp"><a href="bnawq.html">Configuring Beans</a></p>
<p class="toc level4"><a href="bnawq.html#bnawr">Using the <tt>managed-bean</tt> Element</a></p>
<p class="toc level4"><a href="bnawq.html#bnaws">Initializing Properties Using the <tt>managed-property</tt> Element</a></p>
<p class="toc level5"><a href="bnawq.html#bnawu">Referencing a Java <tt>Enum</tt> Type</a></p>
<p class="toc level5"><a href="bnawq.html#bnawv">Referencing an Initialization Parameter</a></p>
<p class="toc level5"><a href="bnawq.html#bnaww">Initializing Map Properties</a></p>
<p class="toc level5"><a href="bnawq.html#bnawx">Initializing Array and List Properties</a></p>
<p class="toc level5"><a href="bnawq.html#bnawy">Initializing Managed Bean Properties</a></p>
<p class="toc level4 tocsp"><a href="bnawq.html#bnaxa">Initializing Maps and Lists</a></p>
<p class="toc level3 tocsp"><a href="bnaxb.html">Registering Custom Error Messages</a></p>
<p class="toc level4"><a href="bnaxb.html#gkuhg">Using <tt>FacesMessage</tt> to Create a Message</a></p>
<p class="toc level4"><a href="bnaxb.html#bnass">Referencing Error Messages</a></p>
<p class="toc level3 tocsp"><a href="bnaxc.html">Registering Custom Localized Static Text</a></p>
<p class="toc level3"><a href="gireb.html">Using Default Validators</a></p>
<p class="toc level3"><a href="bnaxf.html">Configuring Navigation Rules</a></p>
<p class="toc level4"><a href="bnaxf.html#giqwk">Implicit Navigation Rules</a></p>
<p class="toc level3 tocsp"><a href="bnaxj.html">Basic Requirements of a JavaServer Faces Application</a></p>
<p class="toc level4"><a href="bnaxj.html#bnaxk">Configuring an Application With a Web Deployment Descriptor</a></p>
<p class="toc level5"><a href="bnaxj.html#bnaxl">Identifying the Servlet for Lifecycle Processing</a></p>
<p class="toc level5"><a href="bnaxj.html#bnaxm">Specifying a Path to an Application Configuration Resource File</a></p>
<p class="toc level5"><a href="bnaxj.html#bnaxn">Specifying Where State Is Saved</a></p>
<p class="toc level4 tocsp"><a href="bnaxj.html#giqxl">Configuring Project Stage</a></p>
<p class="toc level4"><a href="bnaxj.html#bnaxt">Including the Classes, Pages, and Other Resources</a></p>
<p class="toc level2 tocsp"><a href="gkiow.html">12.&nbsp;&nbsp;Using Ajax with JavaServer Faces Technology</a></p>
<p class="toc level2"><a href="gkhxa.html">13.&nbsp;&nbsp;Advanced Composite Components</a></p>
<p class="toc level2"><a href="bnavg.html">14.&nbsp;&nbsp;Creating Custom UI Components</a></p>
<p class="toc level2"><a href="bnafd.html">15.&nbsp;&nbsp;Java Servlet Technology</a></p>
<p class="toc level2"><a href="bnaxu.html">16.&nbsp;&nbsp;Internationalizing and Localizing Web Applications</a></p>
<p class="toc level1 tocsp"><a href="bnayk.html">Part&nbsp;III&nbsp;Web Services</a></p>
<p class="toc level2"><a href="gijti.html">17.&nbsp;&nbsp;Introduction to Web Services</a></p>
<p class="toc level2"><a href="bnayl.html">18.&nbsp;&nbsp;Building Web Services with JAX-WS</a></p>
<p class="toc level2"><a href="giepu.html">19.&nbsp;&nbsp;Building RESTful Web Services with JAX-RS</a></p>
<p class="toc level2"><a href="gjjxe.html">20.&nbsp;&nbsp;Advanced JAX-RS Features</a></p>
<p class="toc level2"><a href="gkojl.html">21.&nbsp;&nbsp;Running the Advanced JAX-RS Example Application</a></p>
<p class="toc level1 tocsp"><a href="bnblr.html">Part&nbsp;IV&nbsp;Enterprise Beans</a></p>
<p class="toc level2"><a href="gijsz.html">22.&nbsp;&nbsp;Enterprise Beans</a></p>
<p class="toc level2"><a href="gijre.html">23.&nbsp;&nbsp;Getting Started with Enterprise Beans</a></p>
<p class="toc level2"><a href="gijrb.html">24.&nbsp;&nbsp;Running the Enterprise Bean Examples</a></p>
<p class="toc level2"><a href="bnbpk.html">25.&nbsp;&nbsp;A Message-Driven Bean Example</a></p>
<p class="toc level2"><a href="gkcqz.html">26.&nbsp;&nbsp;Using the Embedded Enterprise Bean Container</a></p>
<p class="toc level2"><a href="gkidz.html">27.&nbsp;&nbsp;Using Asynchronous Method Invocation in Session Beans</a></p>
<p class="toc level1 tocsp"><a href="gjbnr.html">Part&nbsp;V&nbsp;Contexts and Dependency Injection for the Java EE Platform</a></p>
<p class="toc level2"><a href="giwhb.html">28.&nbsp;&nbsp;Introduction to Contexts and Dependency Injection for the Java EE Platform</a></p>
<p class="toc level2"><a href="gjbls.html">29.&nbsp;&nbsp;Running the Basic Contexts and Dependency Injection Examples</a></p>
<p class="toc level2"><a href="gjehi.html">30.&nbsp;&nbsp;Contexts and Dependency Injection for the Java EE Platform: Advanced Topics</a></p>
<p class="toc level2"><a href="gkhre.html">31.&nbsp;&nbsp;Running the Advanced Contexts and Dependency Injection Examples</a></p>
<p class="toc level1 tocsp"><a href="bnbpy.html">Part&nbsp;VI&nbsp;Persistence</a></p>
<p class="toc level2"><a href="bnbpz.html">32.&nbsp;&nbsp;Introduction to the Java Persistence API</a></p>
<p class="toc level2"><a href="gijst.html">33.&nbsp;&nbsp;Running the Persistence Examples</a></p>
<p class="toc level2"><a href="bnbtg.html">34.&nbsp;&nbsp;The Java Persistence Query Language</a></p>
<p class="toc level2"><a href="gjitv.html">35.&nbsp;&nbsp;Using the Criteria API to Create Queries</a></p>
<p class="toc level2"><a href="gkjiq.html">36.&nbsp;&nbsp;Creating and Using String-Based Criteria Queries</a></p>
<p class="toc level2"><a href="gkjjf.html">37.&nbsp;&nbsp;Controlling Concurrent Access to Entity Data with Locking</a></p>
<p class="toc level2"><a href="gkjia.html">38.&nbsp;&nbsp;Improving the Performance of Java Persistence API Applications By Setting a Second-Level Cache</a></p>
<p class="toc level1 tocsp"><a href="gijrp.html">Part&nbsp;VII&nbsp;Security</a></p>
<p class="toc level2"><a href="bnbwj.html">39.&nbsp;&nbsp;Introduction to Security in the Java EE Platform</a></p>
<p class="toc level2"><a href="bncas.html">40.&nbsp;&nbsp;Getting Started Securing Web Applications</a></p>
<p class="toc level2"><a href="bnbyk.html">41.&nbsp;&nbsp;Getting Started Securing Enterprise Applications</a></p>
<p class="toc level1 tocsp"><a href="gijue.html">Part&nbsp;VIII&nbsp;Java EE Supporting Technologies</a></p>
<p class="toc level2"><a href="gijto.html">42.&nbsp;&nbsp;Introduction to Java EE Supporting Technologies</a></p>
<p class="toc level2"><a href="bncih.html">43.&nbsp;&nbsp;Transactions</a></p>
<p class="toc level2"><a href="bncjh.html">44.&nbsp;&nbsp;Resource Connections</a></p>
<p class="toc level2"><a href="bncdq.html">45.&nbsp;&nbsp;Java Message Service Concepts</a></p>
<p class="toc level2"><a href="bncgv.html">46.&nbsp;&nbsp;Java Message Service Examples</a></p>
<p class="toc level2"><a href="gkahp.html">47.&nbsp;&nbsp;Advanced Bean Validation Concepts and Examples</a></p>
<p class="toc level2"><a href="gkeed.html">48.&nbsp;&nbsp;Using Java EE Interceptors</a></p>
<p class="toc level1 tocsp"><a href="gkgjw.html">Part&nbsp;IX&nbsp;Case Studies</a></p>
<p class="toc level2"><a href="gkaee.html">49.&nbsp;&nbsp;Duke's Tutoring Case Study Example</a></p>
<p class="toc level1 tocsp"><a href="idx-1.html">Index</a></p>
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<a name="girch"></a><h2>Using Annotations to Configure Managed Beans</h2>
<a name="indexterm-758"></a><a name="indexterm-759"></a><p>JavaServer Faces support for bean annotations has been introduced in <a href="bnaph.html">Chapter&nbsp;4, JavaServer Faces Technology</a>. Bean annotations
can be used for configuring JavaServer Faces applications.</p>

<p>The <tt>@ManagedBean</tt> (<tt>javax.faces.bean.ManagedBean</tt>) annotation in a class automatically registers that class as a
managed bean class with the server runtime. Such a registered managed bean does
not need <tt>managed-bean</tt> configuration entries in the application configuration resource file.</p>

<p>An example of using the <tt>@ManagedBean</tt> annotation in a class is as
follows:</p>

<pre>@ManagedBean
@SessionScoped
public class DukesBday{
...
}</pre><p>The above code snippet shows a bean that is managed by the
JavaServer Faces implementation and is available for the length of that session. You do
not need to configure the managed bean instance in the <tt>faces-config.xml</tt> file.
In effect, it is an alternative to the application configuration resource file approach
and reduces the task of configuring managed beans.</p>

<p>You can also define the scope of the managed bean within the
class file, as shown in the above example. You can annotate beans with
request, session, or application scope, but not view scope.</p>

<p>All classes will be scanned for annotations at startup unless the <tt>faces-config</tt>
element in the <tt>faces-config.xml</tt> file has the <tt>metadata-complete</tt> attribute set to <tt>true</tt>.</p>

<p>Annotations are also available for other artifacts such as components, converters, validators, and
renderers to be used in place of application configuration resource file entries. They
are discussed, along with registration of custom listeners, custom validators, and custom converters,
in <a href="bnavg.html">Chapter&nbsp;14, Creating Custom UI Components</a>.</p>



<a name="gircr"></a><h3>Using Managed Bean Scopes</h3>
<a name="indexterm-760"></a><p>You can use annotations to define the scope in which the bean
will be stored. You can specify one of the following scopes for a
bean class:</p>


<ul><li><p><a name="indexterm-761"></a>Application (<tt>@ApplicationScoped</tt>): Application scope persists across all users' interactions with a web application.</p>

</li>
<li><p><a name="indexterm-762"></a>Session (<tt>@SessionScoped</tt>): Session scope persists across multiple HTTP requests in a web application</p>

</li>
<li><p><a name="indexterm-763"></a>View (<tt>@ViewScoped</tt>): View scope persists during a user's interaction with a single page (view) of a web application.</p>

</li>
<li><p><a name="indexterm-764"></a>Request (<tt>@RequestScoped</tt>): Request scope persists during a single HTTP request in a web application.</p>

</li>
<li><p><a name="indexterm-765"></a>None (<tt>@NoneScoped</tt>):</p>

<p>Indicates a scope is not defined for the application.</p>

</li>
<li><p><a name="indexterm-766"></a>Custom (<tt>@CustomScoped</tt>): A user-defined, nonstandard scope. Its value must be configured as a map. Custom scopes are used infrequently.</p>

</li></ul>
<p>You may want to use <tt>@NoneScoped</tt> when a managed bean references another managed
bean. The second bean should not be in a scope (<tt>@NoneScoped</tt>) if it
is supposed to be created only when it is referenced. If you define
a bean as <tt>@NoneScoped</tt>, the bean is instantiated anew each time that it
is referenced, and so it does not get saved in any scope.</p>

<p>If your managed bean takes part in a single HTTP request, you
should define the bean with a request scope. If you placed the bean
in session or application scope instead, the bean would need to take precautions
to ensure thread safety because component instances depend on running inside of a
single thread.</p>

<p>If you are configuring a bean that allows attributes to be associated with
the view, you can use the view scope. The attributes persist until
the user has navigated to the next view.</p>



<a name="girep"></a><h4>Eager Application-scoped Beans</h4>
<a name="indexterm-767"></a><p>Managed beans are lazily instantiated. That is, that they are instantiated when a
request is made from the application.</p>

<p>To force an application-scoped bean to be instantiated and placed in the application
scope as soon as the application is started and before any request is
made, the <tt>eager</tt> attribute of the managed bean should be set to <tt>true</tt>
as shown in the following example:</p>

<pre>@ManagedBean(eager=true)
@ApplicationScoped</pre>
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